A storage system is available in which a plurality of storage apparatus that incorporates a hard disk drive (HDD), a solid state drive (SSD) or the like are centrally managed by a management server. The management server is coupled to a plurality of storage apparatus through a network such as a LAN (Local Area Network). Each storage apparatus retains management information for managing a storage region such as a logical volume. The management server manages the state of the individual storage apparatus utilizing a management table including the substance of management information retained by the individual storage apparatus.
An operation for a storage region of a storage apparatus is either performed from a management server or is performed directly for the storage apparatus. Where an operation for a storage region is performed directly for a storage apparatus, synchronization of the management information is carried out between the storage apparatus and the management server after the operation. As the synchronization method of management information, for example, a method in which the storage apparatus notifies the management server of the substance of the operation in response to a synchronization request that is periodically issued from the management server and a method in which, after the operation, the storage apparatus voluntarily notifies the management server of the substance of the operation are available.
It is to be noted that, as regards a method for matching the substance of a database, a method has been proposed in which, for example, a difference value between the database upon last matching and the database upon current matching is determined and is used to match the database. Further, a method has been proposed in which a plurality of storage apparatus is separated into a plurality of groups and file management databases of storage apparatus are synchronized with each other for each group. Furthermore, a method has been proposed in which data synchronization is carried out between datacenters the distance between which is small whereas asynchronous remote copying is carried out between datacenters the distance between which is great.
Examples of the related art include Japanese Laid-open Patent Publication No. 10-187514, Japanese Laid-open Patent Publication No. 2005-276094, and Japanese Laid-open Patent Publication No. 2003-122509.